Combining Cloth simulation cache?
... basically you have to rename cached .bphys files.


First enable to Disk Cache checkbox, it gives you an access to saved cache on your disk in .blend directory.
Than Bake caches
Than for safety purpose I would recommend to duplicate whole cache folder.
In blender create one more sim called like MIX or what ever and let bake cache for a whole animation. Doesn't matter what result is produced, just save the blend file.
Inside original cache folder delete all files starts MIX and all previously baked caches let rename with MIX prefix (so the first frame looks like MIX_0000001_00.bphys)


I expect your baked sims continues one after the other like from frames 0-50, 51-100, 101-150

First_0000001_00.bphys ... First_0000050_00.bphys
Second_0000051_01.bphys ... Second_0000100_01.bphys

If they doesn't you would have to rename frame numbers to be sequential as well.

Note:

I see you have baked already, but if you didn't save to disk before and cache is saved into .blend file - I don't know about a way to get them out from .blend and you will have to rebake it.
in some situations can be option to export sims individually as Alembic (.abc) and import .abc back as individual objects and animate their visibility in timeline.